1. Field of the Invention
This invention relates to an integrator system and a method for rapidly determining the effectiveness of a germicidal process for medical equipment.
2. Background
Medical devices are sterilized before use in hospitals, physicians' offices, and other medical facilities. Steam, heat, ethylene oxide, and hydrogen peroxide are commonly used as sterilizing agents.
It is standard practice to include a sterility indicator in a load of articles to be sterilized in a sterilizer. The sterility indicator provides a measure of whether the sterilization process was effective in sterilizing the articles in a particular load. If the sterilization process was not effective, as indicated by the sterility indicator, the load of equipment is rejected for use.
Biological indicators are generally recognized as reliable sterility indicators. The biological indicator includes a carrier that has been inoculated with spores or other microorganisms. Spores are generally utilized in biological indicators, because spores are more resistant to sterilization than other microorganisms.
The biological indicator is placed into the sterilizer with the equipment to be sterilized. At the end of the sterilization process, the biological indicator is removed from the sterilizer, and the carrier is immersed in a sterile culture medium. The culture medium and carrier are incubated for a predetermined time at an appropriate temperature. At the end of the incubation period, it is determined whether any microorganisms have grown in the growth medium. If there is no growth of microorganisms in the growth medium, it is assumed that the equipment in the sterilizer has been properly sterilized. If microorganism growth is observed, the sterilization process was not effective, and the articles in the sterilizer are rejected for use. The growth of microorganisms is determined through a signal such as the generation of turbidity or a color change in a pH indicator due to a pH change from byproducts of cell growth in the medium. Biological indicators are described, for example, in U.S. Pat. Nos. 5,552,320 and 6,436,659, both of which are incorporated herein by reference in their entirety.
Although biological indicators are accurate indicators for the effectiveness of the sterilization cycle, at least 24-48 hours are required to obtain results from the biological indicators. The equipment that was exposed to the sterilization procedure is normally kept in quarantine until the results from the biological indicator are available. Medical equipment is expensive, and storage space in medical facilities is limited. Some hospitals therefore use the equipment before the results are available. Storing quarantined medical equipment is not an efficient use of resources. There is a need for a rapid test for determining the effectiveness of the sterilization process.
Foltz et al. (U.S. Pat. No. 6,355,448) describe a method of determining the effectiveness of a sterilization process by using the activity of enzymes rather than spores. It is stated that the enzyme test procedure requires only a few minutes rather than the several days that are required to obtain the results from biological indicators.
The use of a plurality of enzymes rather than a single enzyme was disclosed in U.S. Pat. Nos. 5,486,459 and 6,528,277. Using a plurality of enzymes was believed to better mimic the response of a microorganism than a single enzyme.
There is a need for sterilization indicators that provide sterilization results rapidly.